enter the dynamic shelf region and become entrained in the mud stream (Weils et al. in 

 press). The time scale for widespread reversal in present coastal erosion along 

 Louisiana's chenier plain is 50 to 100 years, provided that the Atchafalaya River discharge 

 remains relatively constant and no sediment is artifically diverted away from the mud 

 stream. 



CONCLUSIONS 



1. The chenier plain of southwestern Louisiana is presently receiving a major new 

 influx of fine-grained sediment from the Atchafalaya River to the east, the first such 

 sediment pulse in recorded history. Sediment is delivered by the Atchafalaya mud 

 stream, a westerly flowing band of turbid water that may extend 20 km offshore. 



2. Growth of the chenier plain appears initially to be by a series of transitory 

 mudflats, a few of which become welded to the shoreline. The pattern of mudflat 

 sedimentation is increasing and shifting to the west, consistent with the direction of 

 coastal and wave-induced currents. 



3. The Atchafalaya mud stream transports more sediment, by an order of 

 magnitude, to the chenier plain than can be accounted for in yearly mudflat accretion. 

 Much of the sediment may be spread as a thin veneer across the inner continental shelf. 



4. Future development of the chenier plain will be tied intimately to the fate of 

 Atchafalaya Bay. Accelerated growth of the chenier plain is expected when Atchafalaya 

 Bay becomes sediment-filled, thus allowing an even greater volume of sediments to enter 

 the dynamic shelf region seaward of the bay. 



5. Widespread reversal in the present erosional trend is expected in 50 to 100 

 years. 



ACKNOWLEDGMENTS 



Support for this project was provided by the Louisiana Sea Grant University 

 Program, a part of the National Sea Grant University Program, maintained by the 

 National Oceanic and Atmospheric Administration of the U.S. Department of 

 Commerce. Mrs. Gerry Dunn drafted the figures. 



LITERATURE CITED 



Adams, R.D., P.J. Banas, R.H. Baumann, J.H. Blackmon, and W.G. Mclntire. 1978. 

 Shoreline erosion in coastal Louisiana: Inventory and assessment. Final Report to 

 Louisiana Department of Transportation and Development. 139 pp. 



Crout, R.L., and R.D. Hamiter. 1981. Response of bottom waters on the west Louisiana 

 shelf to transient wind events and resulting sediment transport. Trans. Gulf Coast 

 Assoc. Geo). Soc. 31:273-278. 



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